the Coloration of Eygs. 555 



were known and unacceptable — unless^ indeed, it resembled 

 some other well-known egg that was then unacceptable. It 

 is just interesting in this connection to recall the fact that 

 the eggs of the English Cuckoo, even when laid in other 

 nests, most commonly resemble the eggs of Wagtails, Pipits, 

 and some Warblers, and to note that the eggs of Wagtails, 

 Pipits, and, at any rate, some Warblers were not placed very 

 high by my animals, the Pied Wagtail's in particular — not 

 tiiat my mongoose's preferences were necessarily the same 

 as those of English egg-eaters. 



7. Polymorphic Eygs of Weavers. — I refer especially to 

 members of the genus Hyphantornis. Each species lays 

 several different types of egg. The types are well marked 

 and constant, and intermediate forms are relatively rare. 

 Apparently each hen-bird lays only one type. Nearly 

 every form resembles more or less Jstrongly some type of 

 unrelated egg occurring commonly in the same area. The 

 figures in Plate XIX. illustrate this point. 



Mr. G. L. Bates's suggestion ('Ibis,' Oct. 1911, p. 585) 

 that the distinct types of eggs " must aid each hen-bird in 

 finding her own, to the benefit of the race," might account 

 for the distinct types, but not for the resemblances. In any 

 case, we meet with a similar phenomenon in the eggs of many 

 solitarily-nesting Warblers (^pa/i5, Cisticola, Prinia, etc.) to 

 which the suggestion could not apply. I may, of course, 

 be unintentionally exaggerating the resemblances. I think 

 not. And, if not, I am rather tempted to think that we 

 may have here a case of polymorphic mimicry such as 

 occurs in insects in the females of Papilio dardanus, though 

 probably with a fbw larger synaposematic element^ in the ^^*^ 

 mimicry. 



-There is a good deal to be said for the view. I will hold this 

 over till a future occasion, when I hope to discuss the whole 

 problem in some detail. There are also two or three quite 

 strong objections to it — resemblances less good or absent in 

 at least one of the species (and in the Warblers), darkness 

 of some of the nests, characteristic appearance of the nests. 



